为了考察好氧颗粒污泥(aerobic granular sludge,AGS)同步脱氮除磷(simultaneous nitrogen and phosphorus removal,SNPR)能力,以及在低温条件下的适应情况,采用2个SBR反应器(命名为A、B)以厌氧/好氧方式处理实际生活污水,历时254 d.反应器以沉淀时间为选择压,均在20 d内培养获得AGS,在第42 d加入不同附加碳源(分别为丙酸钠+乙酸钠和葡萄糖),调节COD∶N∶P的比例约为360∶60∶6,2个反应器均获得了夏秋季4个月长期稳定的SNPR效果,A的出水NH4^+-N、TIN和PO4^3--P平均去除率分别为98.42%、74.25%和94.79%,B的出水NH4^+-N、TIN和PO4^3--P平均去除率分别为99.45%、75.96%和95.60%;在低温的影响下,2个反应器分别经35 d4、9 d逐渐恢复了稳定的SNPR效果,之后A的出水NH4+-N、TIN和PO4^3--P平均去除率分别为96.33%、79.49%和99.68%,B的出水NH4+-N、TIN和PO4^3--P平均去除率则分别为93.85%、76.44%和98.44%.AGS好氧吸磷和反硝化除磷的同时进行使得除磷优先完成;硝化作用决定着SNPR的反应速度和最终效果;温度过低使得AGS内缺氧区减小,同时胞内PHAs的不足,共同制约反硝化的进行,影响SNPR的效果.
The simultaneous nitrogen and phosphorus removal(SNPR) from real domestic wastewater using aerobic granular sludge(AGS) has been investigated.The effect of temperature changes on the SNPR of AGS was also studied.Two lab-scale sequencing batch reactors(SBRs),named as A and B,were operated for 254 days in alternating anaerobic-aerobic mode.The AGS was cultivated in 20 days using settling time as selection pressure.From the 42nd day onwards, additional carbon(acetate and peptone for A,glucose for B) were added to make the ratio of COD∶N∶P as 360∶60∶6.The SNPR by AGS was achieved for 4 months,and the removal ratios of ammonia,total inorganic nitrogen and phosphorus of A were reached to 98.42%,74.25% and 94.79%,respectively;the removal ratios of ammonia,total inorganic nitrogen and phosphorus of B were reached to 99.45%,75.96% and 95.60%,respectively.Then,the temperature decreased to 9-13℃,which seriously affected the efficiency of SNPR.The removal efficiencies of SNPR of reactor A and B were recovered after 35 days and 49 days,respectively,and the removal ratios of ammonia,total inorganic nitrogen and phosphorus of A were reached to 96.33%,79.49% and 99.68%,respectively;the removal ratios of ammonia,total inorganic nitrogen and phosphorus of B were reached to 93.85%,76.44% and 98.44%,respectively.PAOs and DNPAOs together completed the phosphorus removal and made phosphorus removal faster than nitrogen removal.Nitrification was the rate limiting step for SNPR.The low temperature made the anoxic zone in AGS decrease,together with the absence of PHAs,made denitrification could not complete.